Are Community-Acquired C. Diff Cases on the Rise?

Study suggests that more disease is occurring outside hospital setting

by Michael Smith Michael Smith North American Correspondent, MedPage Today
June 19, 2016

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Note that this study was published as an abstract and presented at a conference. These data and conclusions should be considered to be preliminary until published in a peer-reviewed journal.

BOSTON -- A recent rise in Clostridium difficile in hospitals appears to be driven by infections acquired in the community, a researcher said here.

The CDC estimates that more than 450,000 Americans get a C. difficile infection in any given year and nearly 30,000 of them will die of the disease, with much of the disease associated with hospital admission and antibiotic use.

But there have been signs that community-acquired and community-onset disease is on the rise, according to Andrew DeRyke, PharmD, of Merck, in Kenilworth, N.J.

And analysis of longitudinal data from 154 hospitals over an 8-year period confirms that insight, DeRyke and colleagues reported at the ASM Microbe meeting.

"The implication is that there is more C. diff in the community," DeRyke told MedPage Today.

The information comes from the Care Fusion database of medical supplies giant Becton Dickinson, of Franklin Lakes, N.J. Care Fusion, acquired by Becton Dickinson in 2014, was a company specializing in technologies aimed at reducing medical errors and preventing healthcare-associated infections.

The database contains clinical data from 154 hospitals across the U.S. from 2008 through 2015, which allowed the researchers to look at trends in C. difficile diagnoses in hospital over time.

As expected, he said, the data show a 71% rise in incidence from 14,686 cases in 2008 to 25,151 in 2015.

But a closer look suggested that the traditional type of C. difficile case -- acquired in hospital after exposure in hospital -- was not the important driver in the increase, DeRyke said.

For the analysis, a C. difficile case was defined as either a positive result from a test for a C. difficile toxin or molecular assay of a stool specimen obtained from a patient showing the presence of the bacteria without a positive test in the previous 8 weeks.

The investigators classified the cases based on the specimen collection time and setting:

Hospital-onset cases -- historically the most important category -- were those that occurred more than 3 days after admission.

Community-onset and community-associated cases were defined as occurring in an outpatient setting or no more than 3 calendar days after hospital admission but with no hospital admission in the previous 12 weeks.

Community-onset and hospital-associated cases were defined similarly except that patients had been admitted to hospital -- even overnight -- within the past 12 weeks.

The analysis showed that the hospital-onset cases rose by a factor of 1.33 from 3,555 in 2008 to 4,740 in 2015, while the community-onset and hospital-associated cases rose by 1.42, from 4,545 to 6,460 cases.

In sharp contrast, the community-onset and community-associated cases more than doubled from 6,586 to 13,951 cases, a factor of 2.12, DeRyke and colleagues found.

DeRyke cautioned that the study covered a period in which hospitals were switching from a test that detected the expression of the disease-causing C. difficile toxins to one that simply detects the gene for them, which might have inflated the case numbers.

But in that case, he said, the inflated rates would be seen across the board, rather than differing based on the setting.

That might not be entirely correct, commented David Aronoff, MD, of Vanderbilt University in Nashville, especially if outpatient clinics had preferentially switched to the newer test that does not detect toxin expression.

"I do think that these data suggest ... that there's more C. diff, but [the analysis] hasn't been adjusted for the way it's diagnosed and that's just a caveat," Aronoff told MedPage Today.

The findings imply that it will be important to get a handle on the risk factors that might be involved in the increase of community-associated C. difficile, he said, including the traditional issue of antibiotic use, but also such things as smoking, nutrition, and frequent encounters with the healthcare system.

"We don't want to have C. diff anywhere, but particularly in the community where it feels as if we might have less control over the problem," he noted.

Because of the issue of resistance and other adverse effects, Aronoff said, there is increasing interest in using antibiotics carefully and appropriately -- something that might over time reduce the incidence of the C. difficile disease.

"The discipline of antimicrobial stewardship is continuing to mature, and that should bring downstream benefits in terms of reducing an individual's and a population's risk for opportunistic infections like C. diff," he stated.

The study was supported by Merck. DeRyke and some co-authors are company employees.

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